The present invention relates to a sound increase apparatus which is capable of improving sound quality of an intake sound generated from an engine inlet pipe of automotive engine.
In recent years, there have been proposed and developed various sound increase apparatus which increase or strengthen an intake sound and convey it to a vehicle cabin. One such sound increase apparatus has been disclosed in Japanese Patent Provisional Publication No. 2004-218458 (hereinafter is referred to as “JP2004-218458”). In JP2004-218458, an air induction part is provided for intake of air, and is connected to one end of an air intake duct through an air cleaner. The other end of the air intake duct is connected to an engine. The air induction part is formed with an opening on a side wall thereof, and the opening and a dash panel are connected by flexible tubes. An intake sound resulting from air pulsation that propagates through the inside of the flexible tubes is conveyed into a vehicle cabin via the dash panel. And thus, a sporty intake sound can be rendered in the cabin.